1. Field of the Invention
The invention relates to containment techniques for preventing the undesirable discharge of chemical materials onto the ground and, more particularly, to a containment apron that can be positioned conveniently beneath a railroad tank car or other vehicle or container so as to collect any inadvertent spills or leaks.
2. Description of the Prior Art
Traditionally, railroad tank car loading and unloading has been relatively unregulated. In the past, railroad sidings reflected that lack of concern because they had no provision to collect accidental discharges of whatever was being loaded and unloaded. Often the commodity being shipped was inexpensive or perceived to be of little environmental impact, and therefore any spills were either hosed down or just left for the next rain to clear away. With the advent of stiff fines and high soil remediation costs, techniques to capture these accidental releases and prevent spills or eliminate adverse environmental consequences have become both financially important and of primary interest to the health and safety of the community.
Since spills most often occur during a loading or unloading operation while a railroad tank car is stationary, relatively large, stationary spill containment pans have been developed to collect and possibly economically reuse spilled chemicals. Examples of such spill containment pans are disclosed in U.S. Pat. No. 5,435,458 and U.S. Ser. No. 08/727,964, both invented by Merrill E. Bishop. A transportable spill containment pan is disclosed in U.S. Pat. No. 5,775,869, also invented by Merrill E. Bishop. The latter device enables spills to be collected at locations other than at fixed sidings where permanent spill containment pans may be provided.
Prior efforts to collect leaking, dripping and spilled materials, particularly oily materials, have included providing a flexible plastic drop cloth or sheet which forms a barrier to prevent contact of the oily material with the ground. The plastic sheet can be suspended or mounted to the underside of an automobile, as in U.S. Pat. No. 4,935,418. Alternatively, a spill containment bag can be attached to a tanker truck or railroad tank car as disclosed in U.S. Pat. Nos. 4,707,969 and 5,339,872. Such products have been advertised by ILC Dover of Frederica, Del. under the trademarks SPILL SAVER, FUEL SAVER, AND DRIP CATCHER.
While certain of the referenced devices presumably could be attached to a leaking tank truck or railroad tank car, the devices fail to address certain problems. Often, it is necessary or desirable in the interest of public safety and health to move a leaking tank truck or railroad tank car to a more remote location where the leak can be repaired. The referenced devices are not suitable for use with a vehicle that must be moved due to interference with the ground or portions of the vehicle. Even if movement of the vehicle were possible, at least a portion of any collected liquid would be released from the device due to wave action that would occur upon movement of the vehicle itself or movement of the emergency spill containment.
Desirably, a spill containment apparatus for use with railroad tank cars or other liquid-containing vehicles would be compact and lightweight for purposes of transportation, but would be able to be reconfigured on site and attached to the vehicle to provide an adequate collection volume beneath the vehicle. Preferably, any such device would be able to be quickly and easily attached to the vehicle, would be able to collect a large amount of liquid, would permit the vehicle to be moved while leaking liquid is being collected, and would prevent liquid from being discharged from the device while vehicle movement is occurring. Further, any such device would be able to be emptied easily without danger of spilling its contents or exposing workers to dangerous contact with the collected liquid or bulk material.